Question: Simplify the following expression: $k = \dfrac{10z - 10y}{25y} + \dfrac{15z + 5}{25y}$ You can assume $x,y,z \neq 0$.
Since the expressions have the same denominator we simply combine the numerators: $k = \dfrac{10z - 10y + 15z + 5}{25y}$ $k = \dfrac{25z - 10y + 5}{25y}$ The numerator and denominator have a common factor of $5$, so we can simplify $k = \dfrac{5z - 2y + 1}{5y}$